JP2019117107A - Line scanner - Google Patents

Abstract

To enable detection objects differing in type and size to be image sensed at low cost.SOLUTION: On a base 111 conveyed in the direction of an axis Z by a conveyance unit 12 are arranged a transmit/receive unit 112 for transmitting/receiving a terahertz wave and measuring the three-dimensional shape of a detection object, a scan mirror 94 for reflecting the terahertz wave transmitted from the transmit/receive unit 112 at an angle changing with the passage of time, and an objective lens 95 for causing the terahertz wave reflected by the scan mirror 94 to be converged toward the detection object. The scan mirror 94 is removably held by a scan mirror holding unit 113 whose position and angle are adjustable. The objective lens 95 is removably held by an object lens holding unit 114 whose position is adjustable. A user can change the scan mirror 94 and the objective lens 95 in accordance with the type and size of the detection object.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technology for performing image sensing by electromagnetic waves.

  As an apparatus for performing image sensing of a detection target using electromagnetic waves such as terahertz waves (hereinafter, THz waves), for example, an apparatus having a configuration shown as a line scanner 9 in FIG. 9 is known.

  The line scanner 9 includes a transmitting unit 91 for transmitting a THz wave, a lens 92 for adjusting the THz wave transmitted from the transmitting unit 91 in a parallel state, and a part (for example, 50%) of the THz wave transmitted through the lens 92. A half mirror 93 that transmits the light and reflects the rest toward the reference mirror 98, a scan mirror 94 that reflects the THz wave transmitted through the half mirror 93 toward the detection target 8 at a periodically changing angle, and a scan mirror 94 And an objective lens 95 for adjusting the THz wave in parallel.

  The line scanner 9 further reflects the THz wave reflected by the half mirror 93 after reflecting on the surface of the detection target 8 and transmitting through the objective lens 95, and receiving the THz wave transmitted through the lens 96 The processor 97 is provided with an arithmetic unit 99 for calculating the relative positional relationship of the position of the surface of the detection target 8 at which the THz wave is reflected, based on the intensity of the THz wave received by the receiver 97.

  In the THz wave transmitted from the line scanner 9, the angle toward the detection target 8 is periodically changed by the scan mirror 94. Therefore, the position at which the THz wave is transmitted to the surface of the detection target 8 moves in the Y-axis direction in FIG. Further, while the line scanner 9 transmits a THz wave, the line scanner 9 is moved in the Z-axis direction of FIG. 9 by a transport device (not shown). As a result, the surface of the detection target 8 facing the objective lens 95 is scanned in two dimensions in the Y-axis direction and the Z-axis direction. The set of relative distances calculated by the calculation unit 99 with respect to each point on the surface of the detection target 8 scanned by the THz wave represents the three-dimensional shape of the surface of the detection target 8.

  A part of the THz wave transmitted from the transmission unit 91 is reflected by the half mirror 93 and then reflected by the reference mirror 98, passes through the half mirror 93 and the lens 96, and reaches the reception unit 97. The calculating unit 99 is a THz wave that is reflected by the detection target 8 and reaches the receiving unit 97 among the THz waves simultaneously transmitted from the transmitting unit 91 and a THz wave that is reflected by the reference mirror 98 and reaches the receiving unit 97 The absolute distance from the reference position to the detection target 8 is calculated based on the difference in arrival time of

  Patent Document 1 is an example of patent documents disclosing a technique for imaging a detection target using THz waves. Patent Document 1 discloses a THz wave generating element or detecting element, a first lens in contact with the generating element or detecting element, and a second lens disposed opposite to the generating element or detecting element in the optical axis direction with the first lens. There is disclosed a terahertz wave measuring apparatus capable of adjusting an optical system so as to reduce an adverse effect due to interference by having position adjusting means movable integrally in the optical axis direction.

JP, 2015-87163, A

  Conventionally, the line scanner 9 in which the types and parameters (period, amplitude, etc.) of the half mirror 93 and the objective lens 95, the size of the objective lens 95, etc. are adjusted according to the type and size of the detection target 8 is individually designed. Need to manufacture, cost was high.

  SUMMARY OF THE INVENTION In view of the above-described circumstances, the present invention provides means for enabling image sensing of detection targets of different types and sizes at low cost.

  In order to solve the problems described above, the present invention provides a line scanner that transmits and receives electromagnetic waves, and is configured to hold a scan mirror and an objective lens in a removable manner as a first aspect.

  According to the line scanner of the first aspect, by replacing the scan mirror and the objective lens, image sensing of detection targets of different types and sizes can be reduced without requiring design and manufacture of a new line scanner. It can be done at cost.

  In the line scanner according to the first aspect described above, a configuration may be adopted as the second aspect, including an angle adjustment mechanism that adjusts the reference angle of the scan mirror with respect to the transmission direction of the electromagnetic wave.

  In the line scanner according to the first or second aspect described above, a configuration may be adopted as a third aspect that includes a position adjustment mechanism that adjusts the position of the scan mirror in the direction perpendicular to the transmission direction of the electromagnetic wave.

  According to the line scanner of the second or third aspect, it is possible to easily adjust the deviation of the optical axis even when the scan mirror is replaced.

  In the line scanner according to any one of the first to third aspects, the configuration in which objective lenses having different diameters are detachably held may be adopted as a fourth aspect.

  According to the line scanner of the fourth aspect, it is easy to replace objective lenses having different diameters.

  In the line scanner according to any one of the above first to fourth aspects, the transmission plate is provided which transmits the electromagnetic wave transmitted when the rotation center of the scan mirror is on the transmission direction of the electromagnetic wave with the maximum transmittance. The configuration may be adopted as the fifth aspect.

  According to the line scanner of the fifth aspect, it is possible to confirm the presence or absence of the deviation of the optical axis when replacing the scan mirror, and the adjustment of the deviation of the optical axis can be easily performed.

  In the line scanner according to any one of the above first to fifth aspects, a configuration may be adopted as a sixth aspect that includes an angle measurement unit that measures the angle of the scan mirror with respect to the transmission direction of the electromagnetic wave.

  According to the line scanner of the sixth aspect, the angle of the scan mirror can be confirmed, and the installation angle of the scan mirror can be easily adjusted.

  Furthermore, the present invention may adopt, as a seventh aspect, a scanner system including the line scanner according to any one of the above first to sixth aspects, and a transport unit that transports the line scanner.

  According to the scanner system of the seventh aspect, the detection target can be scanned in a two-dimensional direction.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the scanner system which concerns on one Embodiment. FIG. 1 is an external view of a scanner system according to an embodiment. FIG. 2 is a plan view of a scan mirror holder according to an embodiment. FIG. 2 is an external view of an objective lens holder according to an embodiment. The external appearance figure of the permeation | transmission board holder which concerns on one Embodiment, and a permeation | transmission board. The figure for demonstrating the role of the permeation | transmission board which concerns on one Embodiment. The figure for demonstrating the role of the optical sensor which concerns on one Embodiment. The figure which illustrated the position and shape of the transmission board concerning one modification. The block diagram of the line scanner which concerns on a prior art.

[Embodiment]
Hereinafter, a scanner system 1 according to an embodiment of the present invention will be described. FIG. 1 is a view schematically showing the configuration of the scanner system 1. The scanner system 1 includes a line scanner 11 that scans a detection target 8 in the Y-axis direction, and a transport unit 12 that transports the line scanner 11 in the Z-axis direction.

  In FIG. 1, among the components provided in the line scanner 11, the same components as the components provided in the line scanner 9 shown in FIG. 9 are denoted by the reference numerals used in FIG. 9. The line scanner 11 has a base 111 on which the other components of the line scanner 11 are placed and placed, a transmission / reception unit 112, a scan mirror holder 113, and a scan mirror removably attached to the scan mirror holder 113. 94, an objective lens holding portion 114, an objective lens 95 removably attached to the objective lens holding portion 114, a transmission plate holder 115 disposed between the scan mirror holding portion 113 and the objective lens holding portion 114, and transmission A transmission plate 116 removably attached to the plate holder 115 is provided.

  The transmission / reception unit 112 includes a housing 1121, a transmission unit 91 housed in the housing 1121, a lens 92, a half mirror 93, a lens 96, a reception unit 97, a reference mirror 98, a calculation unit 99, a light sensor 1122, a light sensor 1123 is provided. The roles of the light sensor 1122 and the light sensor 1123 will be described later.

  FIG. 2 is an external view of the scanner system 1. FIG. 2 (a) shows the appearance when the scanner system 1 is viewed obliquely from above, and FIG. 2 (b) shows the appearance when the scanner system 1 is seen in the direction of arrow A shown in FIG. .

  The base 111 provided in the line scanner 11 is a plate-like member, and the transmission / reception unit 112, the scan mirror holding unit 113, the objective lens holding unit 114, and the transmission plate holder 115 are disposed thereon. The scan mirror holder 113 detachably holds the scan mirror 94. The objective lens holding unit 114 detachably holds the objective lens 95. A transmission plate 116 is attached to the transmission plate holder 115. The transmission plate holder 115 attached to the transmission plate 116 is attached to the base 111 when adjusting the position and angle of the scan mirror 94, and when the detection target 8 is scanned by the scanner system 1, the transmission plate holder 115 is moved from the base 111 It is removed.

  The transport unit 12 moves the support 121 arranged so that the longitudinal direction is along the Z-axis direction, the connecting unit 122 connecting the support 121 and the line scanner 11, and the connecting unit 122 along the support 121 in the Z-axis direction It has an axial screw 123 which plays a role of causing the motor 124 to rotate, and a motor 124 which rotates the axial screw 123.

  A groove F having a trapezoidal horizontal cross section extending along the Z-axis direction is provided on the surface of the column 121 facing the line scanner 11. Further, on the surface of the connecting portion 122 facing the support column 121, a protrusion fitted with the groove F is provided. Further, the connecting portion 122 is provided with a screw hole penetrating in the Z-axis direction, and the axial screw 123 is screwed into the screw hole. Therefore, when the shaft screw 123 is rotated by the motor 124, the connecting portion 122 locked by the projection fitted under the groove slides along the support column 121, and the line scanner 11 attached to the connecting portion 122 is the Z axis. It is transported in the direction.

  FIG. 3 is a plan view of the scan mirror holder 113. The scan mirror holder 113 includes a rectangular plate 1131 disposed on the base 111, a rectangular plate 1132 disposed on the plate 1131, and a circular plate 1133 disposed on the plate 1132. .

  In the vicinity of both ends in the X-axis direction of the plate 1131, elongated holes elongated in the Y-axis direction are provided, and a pan screw is disposed such that the axis passes through the elongated holes. The screw portions of these pan screws are screwed into screw holes (not shown) provided in the base 111.

  In the vicinity of both ends in the Y-axis direction of the plate 1132, elongated holes elongated in the X-axis direction are provided, and a pan screw is disposed such that the axis passes through the elongated holes. The screw portions of these pan screws are screwed into screw holes (not shown) provided in the plate 1131.

  In the vicinity of both ends of the plate 1133 in the Y-axis direction, long holes having a shape that draws an arc along the outer edge of the plate 1133 are provided, and pan screws are arranged such that the shafts pass through those long holes. There is. The threads of these pan screws are screwed into screw holes (not shown) provided in the plate 1132.

  A rectangular groove G is provided on the top surface of the plate 1133. The user can attach the scan mirror 94 to the scan mirror holder 113 by inserting the scan mirror 94 into the groove G. Also, the user can remove the scan mirror 94 from the scan mirror holder 113 by removing the scan mirror 94 inserted into the groove G. The user can easily construct the line scanner 11 including the scan mirror 94 of various specifications by attaching the scan mirror 94 having different specifications to the scan mirror holding unit 113.

  The user adjusts the position of the scan mirror 94 in the Y-axis direction by loosening the pan screws attached to the long holes of the plate 1131 and moving the plate 1131 in the Y-axis direction and then tightening those pan screws. be able to. That is, the scan mirror holding unit 113 plays a role as a position adjustment mechanism that adjusts the position of the scan mirror 94 in the Y axis direction (the transmission direction of the THz wave transmitted from the line scanner 11).

  The user adjusts the position of the scan mirror 94 in the X axis direction by loosening the pan screws attached to the long holes of the plate 1132 and moving the plates 1132 in the X axis direction and then tightening those pan screws. be able to. That is, the scan mirror holding unit 113 plays a role as a position adjustment mechanism that adjusts the position of the scan mirror 94 in the X-axis direction (direction perpendicular to the transmission direction of the THz wave transmitted from the line scanner 11).

  The user adjusts the reference angle of the scan mirror 94 by loosening the pan screw attached to the long hole of the plate 1133 and rotating the plate 1133 around the center point of the plate 1133 and then tightening those pan screws be able to. That is, the scan mirror holding unit 113 plays the role of an angle adjustment mechanism that adjusts the reference angle of the scan mirror 94 with respect to the Y-axis direction (transmission direction of the THz wave transmitted from the line scanner 11). The reference angle of the scan mirror 94 means an angle serving as a reference of the rotation angle of the scan mirror 94, and for example, with respect to the Y axis direction (or X axis direction) of the scan mirror 94 when the rotation angle is 0 degree. It is an angle.

  FIG. 4 is an external view of the objective lens holder 114. FIG. 4A shows the appearance of the objective lens holding portion 114 as viewed from above, and FIG. 4B shows the objective lens holding portion 114 in the direction of arrow B shown in FIG. 4A. The appearance is shown, and FIG. 4C shows the appearance when the objective lens holding portion 114 is viewed in the direction of the arrow C shown in FIG. 4B.

  The objective lens holding unit 114 includes a rectangular plate 1141 disposed on the base 111 and a lens holder 1142 disposed on the plate 1141.

  In the vicinity of both ends in the Y-axis direction of the plate 1141, elongated holes elongated in the X-axis direction are provided, and a pan screw is disposed such that the axis passes through the elongated holes. The screw portions of these pan screws are screwed into screw holes (not shown) provided in the base 111.

  The lens holder 1142 includes a support 11421, an annular frame 11422 connected on the support 11421, and three support wings 11423 attached to the frame 11422. The horizontal cross section of the column 11421 is rectangular, and the user can attach the lens holder 1142 to the plate 1141 by inserting the lower end of the column 11421 into a rectangular groove (not shown) provided on the upper surface of the plate 1141. . Also, the user can remove the lens holder 1142 from the plate 1141 by pulling out the support column 11421 inserted in the groove of the plate 1141.

  The support wing 11423 is rotatably attached to the frame 11422 about a horizontal axis, and biased toward the center of the frame 11422 by a spring (not shown). A groove is provided on the side surface of the support wing 11423, and the user inserts the collar portion provided on the outer periphery of the objective lens 95 into each of the grooves of the plurality of support wings 11423 to thereby make the lens holder It can be attached to the 1142. The objective lens 95 attached to the lens holder 1142 is stably held at the center position of the frame 11422 in a state where the objective lens 95 is pressed toward the center by the support wings 11423.

  In addition, the user pushes each of the support wings 11423 in a state where the ridges of the objective lens 95 held by the lens holder 1142 are inserted into the grooves toward the outside of the frame 11422 to support the ridges of the objective lens 95. The objective lens 95 can be removed from the lens holder 1142 by removing it from the groove 11423.

  The lens holder 1142 can hold objective lenses 95 of different diameters within a range that can be held by the rotating support wings 11423. That is, the objective lens holding unit 114 has a mechanism for detachably holding the objective lenses 95 having different diameters.

  However, since the diameter of the objective lens 95 that can be held by one lens holder 1142 is limited within a predetermined range, for example, the lens holder 1142 that can hold the objective lens 95 having a diameter of 10 cm to 15 cm, and the diameter of 15 cm to 20 cm Lens holder 1142 capable of holding the objective lens 95 of the above, and a lens holder 1142 capable of holding the objective lens 95 having a diameter of 20 cm to 25 cm; 1142 is being prepared. By attaching a lens holder 1142 of a suitable size to the plate 1141 and attaching the objective lens 95 to the lens holder 1142, the user can easily construct the line scanner 11 including the objective lenses 95 of various diameters.

  The user adjusts the position of the objective lens 95 in the X-axis direction by loosening the pan screw attached to the long hole of the plate 1141 and moving the plate 1141 in the X-axis direction and then tightening those pan screws. be able to. That is, the objective lens holding unit 114 plays a role as a position adjustment mechanism that adjusts the position of the objective lens 95 in the X axis direction (direction perpendicular to the transmission direction of the THz wave transmitted from the line scanner 11).

  FIG. 5 is a view showing the appearance of the transmission plate holder 115 and the transmission plate 116 as viewed in the X-axis direction. The transmission plate holder 115 includes a support 1151 and an annular frame 1152 connected to the support 1151. The horizontal cross section of the column 1151 is rectangular, and the user mounts the transmission plate holder 115 to the base 111 by inserting the lower end of the column 1151 into a rectangular groove (not shown) provided on the upper surface of the base 111. be able to. In addition, the user can remove the transmission plate holder 115 from the base 111 by removing the columns 1151 inserted in the grooves of the base 111.

  The transmission plate 116 has, for example, a shallow dome shape, and transmits THz waves incident perpendicularly to the curved surface with the highest transmittance. The transmission plate 116 is a THz wave with maximum transmittance when the rotation center of the scan mirror 94 is on the transmission direction of the THz wave and on a straight line perpendicular to the objective lens 95 and passing through the center of the objective lens 95. The position is adjusted so as to transmit.

  FIG. 6 is a view for explaining the role of the transmission plate 116. As shown in FIG. In FIG. 6A, the center of rotation of the scan mirror 94 is on the transmission direction of the THz wave transmitted from the transmission unit 91, and on a straight line perpendicular to the objective lens 95 and passing the center of the objective lens 95. , The position of the scan mirror 94 is correctly adjusted. In the state shown in FIG. 6A, the THz wave reflected by the scan mirror 94 is incident substantially perpendicularly on the curved surface of the transmission plate 116 regardless of the rotation angle of the scan mirror 94. Therefore, in this case, the intensity of the THz wave transmitted through the transmission plate 116 does not change with the rotation angle of the scan mirror 94.

  FIG. 6B shows a state in which the position of the rotation center of the scan mirror 94 is not properly adjusted. In the state of FIG. 6B, the angle at which the THz wave reflected by the scan mirror 94 is incident on the curved surface of the transmission plate 116 differs depending on the rotation angle of the scan mirror 94. Therefore, in this case, the intensity of the THz wave transmitted through the transmission plate 116 changes according to the rotation angle of the scan mirror 94.

  The user observes the intensity of the THz wave received by the receiving unit 97 while changing the rotation angle of the scan mirror 94, and adjusts the positions of the plate 1131 and the plate 1132, whereby the rotation center of the scan mirror 94 is properly positioned. Can be adjusted to

  FIG. 7 is a diagram for explaining the roles of the light sensor 1122 and the light sensor 1123. Each of the light sensor 1122 and the light sensor 1123 is a sensor that emits light toward the scan mirror 94, receives light reflected by the detection target 8 and returns from the scan mirror 94, and measures the intensity of the received light . The light sensor 1122 and the light sensor 1123 are connected to the calculation unit 99, and the timing of light emission by the light sensor 1122 and the light sensor 1123 is controlled by the calculation unit 99. Further, the intensity of the reflected light measured by the light sensor 1122 and the light sensor 1123 is output to the calculation unit 99.

  The computing unit 99 measures the time from the timing of light emission by the light sensor 1122 to the timing of light reception of the reflected light of the emitted light (hereinafter, referred to as “time RTT1”). In addition, the calculation unit 99 also measures the time from the light emission timing to the light reception timing of the reflected light of the emitted light (hereinafter, referred to as “time RTT2”) for the light sensor 1123.

  The time RTT1 and the time RTT2 change depending on the rotation angle of the scan mirror 94, and also change largely depending on the distance between the scan mirror 94 and the detection target 8. However, the time difference between the time RTT1 and the time RTT2 (hereinafter referred to as "time difference DT") is not affected by the distance between the scan mirror 94 and the detection target 8, and is affected only by the rotation angle of the scan mirror 94.

  The arithmetic unit 99 stores a table (hereinafter referred to as “rotational angle table”) indicating the correspondence between the rotational angle of the scan mirror 94 and the time difference DT. The calculation unit 99 continuously calculates the time difference DT while the scan mirror 94 is in operation, and refers to the rotation angle table to specify the rotation angle corresponding to the calculated time difference DT. As a result, the computing unit 99 can recognize the rotation angle of the scan mirror 94 in real time. As described above, the light sensor 1122, the light sensor 1123, and the calculation unit 99 function as an angle measurement unit that measures the angle of the scan mirror 94 with respect to the transmission direction of the THz wave.

  The rotation angle of the scan mirror 94 specified by the calculation unit 99 may be used, for example, for notification to the user, or may be used for control of the operation of the scan mirror 94 by the calculation unit 99.

  According to the line scanner 11 described above, the three-dimensional shape of the detection object 8 of various types and sizes is measured by replacing the scan mirror 94 and the objective lens 95 according to the type and size of the detection object 8 be able to. Therefore, compared with the case where a line scanner is individually designed and manufactured according to the kind and size of detection object 8, labor and cost are reduced.

  The scanner system 1 described above is an embodiment of the present invention, and may be variously modified within the scope of the technical idea of the present invention. The following shows examples of such modifications. In addition, 2 or more of the following modifications may be combined suitably.

(1) In the embodiment described above, the transmission plate 116 is disposed between the scan mirror 94 and the objective lens 95. Alternatively, the transmission plate 116 may be disposed between the objective lens 95 and the detection target 8. FIG. 8 is a diagram illustrating the position and shape of the transmission plate 116 in this modification.

(2) In the embodiment described above, the transport unit 12 transports the line scanner 11. Instead of this, the transport unit 12 may transport the detection target 8.

(3) The configuration of the transmission / reception unit 112 described in the above-described embodiment is an example, and a transmission / reception unit having another configuration may be employed. For example, if it is not necessary to measure the absolute distance from the reference position to the detection target 8, the transmission and reception unit 112 may be provided with a light absorbing plate instead of the reference mirror 98.

(4) The specific shape, arrangement, and size of each component of the scanner system 1 described in the above embodiment, the mechanism of the holding mechanism, the mechanism of the adjustment mechanism, and the like are examples, and other shapes, arrangements, The size, the mechanism of the holding mechanism, the mechanism of the adjusting mechanism, etc. may be adopted.

(5) In the scanner system 1 described in the above-described embodiment, the terahertz wave is used to measure the three-dimensional shape of the detection target, but as long as it is an electromagnetic wave that is reflected by a mirror and can be converged by a lens, An electromagnetic wave of any frequency band may be used.

(6) In the drawings of the embodiments described above, the scanning mirror is of a type in which the mirror vibrates (reciprocates) around the rotation center, but the system of the scanning mirror is not limited to this. For example, a scan mirror of a type using a polygon mirror that changes the direction of reflecting the electromagnetic wave while rotating in one direction may be employed.

DESCRIPTION OF SYMBOLS 1 ... Scanner system, 8 ... Detection object, 9 ... Line scanner, 11 ... Line scanner, 12 ... Transport part, 91 ... Transmission part, 92 ... Lens, 93 ... Half mirror, 94 ... Scan mirror, 95 ... Objective lens, 96 ... lens ... 97 reception unit 98 98 reference mirror 99 arithmetic unit 111 base 112 transmission / reception unit 113 scan mirror holding unit 114 objective lens holding unit 115 transmission plate holder 116 Transmissive plate 121 post 122 connecting portion 123 axial screw 124 motor 1121 housing 1122 light sensor 1123 light sensor 1131 plate 1132 plate 1133 plate 1141 Plate, 1142 ... lens holder, 1151 ... post, 1152 ... frame, 11421 ... post, 11422 ... frame, 1142 ... support feather

Claims (7)

  A line scanner that transmits and receives electromagnetic waves, and configured to detachably hold a scanning mirror and an objective lens.   The line scanner according to claim 1, further comprising an angle adjusting mechanism for adjusting a reference angle of the scan mirror with respect to the transmission direction of the electromagnetic wave. The line scanner according to claim 1, further comprising an alignment mechanism that adjusts the position of the scan mirror in the direction perpendicular to the transmission direction of the electromagnetic wave. The line scanner according to any one of claims 1 to 3, wherein objective lenses having different diameters are detachably held. The line scanner according to any one of claims 1 to 4, further comprising: a transmission plate that transmits the electromagnetic wave transmitted when the center of rotation of the scan mirror is in the transmission direction of the electromagnetic wave with the maximum transmittance. The line scanner according to any one of claims 1 to 5, further comprising an angle measurement unit configured to measure an angle of the scan mirror with respect to the transmission direction of the electromagnetic wave. A line scanner according to any one of claims 1 to 6,
And a transport unit for transporting the line scanner.

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